netcore 2.2 封装 AutoMapper

在上篇中我们通过创建一个类并继承automapper的profile类

    public class mappings : profile
    {
        public mappings()
        {
            createmap<userdto, tbuser>();
        }
    }

这样做有一种弊端，就是当传输对象很多的时候，还需要手动一个个的配置映射关系，维护起来相对来说也比较麻烦。

封装automapper

创建automapperextension扩展类

    /// <summary>
    /// automapper扩展类
    /// </summary>
    public static class automapperextension
    {
        /// <summary>
        /// 将源对象映射到目标对象
        /// </summary>
        /// <typeparam name="t">实体类型</typeparam>
        /// <param name="obj">源对象</param>
        /// <returns>转化之后的实体</returns>

        public static t mapto<t>(this object obj)
        {
            if (obj == null) throw new exception("异常");
            var config = new mapperconfiguration(ctx => ctx.createmap(obj.gettype(), typeof(t)));
            var mapper = config.createmapper();
            return mapper.map<t>(obj);
        }

        /// <summary>
        /// 将源对象映射到目标对象
        /// </summary>
        /// <typeparam name="t">实体类型</typeparam>
        /// <param name="dto">源对象</param>
        /// <param name="entity">目标对象</param>
        /// <returns>转化之后的实体</returns>
        public static t map<t>(object dto, t entity)
        {
            var config = new mapperconfiguration(ctx => ctx.createmap(dto.gettype(), typeof(t)));
            var mapper = config.createmapper();
            var newmodel = mapper.map(dto, entity);
            return newmodel;
        }
    }

修改业务层

去掉构造函数中imapper注入

去掉启动类startup.cs中 services.addautomapper(typeof(mappings)) 方法

        /// <summary>
        /// 添加用户
        /// </summary>
        /// <param name="dto">实体传输对象</param>
        /// <returns></returns>
        public int add(userdto dto)
        {
            //var info = _mapper.map<userdto, tbuser>(dto);
            var info = dto.mapto<tbuser>();
            info.addtime = datetime.now;
            info.userid = guid.newguid().tostring("n");
            //var user = new tbuser
            //{
            //    userid = guid.newguid().tostring("n"),
            //    email = dto.email,
            //    username = dto.username,
            //    addtime = datetime.now
            //};
            _dbcontext.add(info);
            return _dbcontext.savechanges();
        }
        /// <summary>
        /// 编辑用户信息
        /// </summary>
        /// <param name="dto">实体传输对象</param>
        /// <returns></returns>
        public int update(userdto dto)
        {
            var user = _dbcontext.tbusers.find(dto.userid);
            if (user == null) throw new exception("获取用户信息失败");
            //user.username = dto.username;
            //user.email = dto.email;
            automapperextension.map(dto, user);
            return _dbcontext.savechanges();
        }

运行测试

跟封装前一样的效果